VEGETABLE FATS AND OILS

For the past 50 years the cultivation of oil-bearing plants has increased considerably. Some seeds such as sunflower kernels and various nuts as well as olives, the fruits of the olive tree, are consumed without much processing. These agricultural products are rich in both nutritionally valuable oil and protein. The same is true for 'Tofu' and related Far Eastern food items which can be produced from whole soybeans by fairly simple procedures. The combination of 'aqueous extraction' and 'membrane isolation techniques' permits the large-scale production of food containing both the protein and high, medium or low levels of oil. By far the major portion of oilseeds and fruits harvested world-wide is being used for the production of edible oils. Phospholipids, sterols, and vitamins are valuable by-products of oil processing. About 10% of the total edible oil produced plus comparatively small proportions of inedible oils are being utilized as industrial raw material. Throughout the world, soya is the most important oil crop, both in the food and the non-food areas. In Europe, rape and sunflower are the major crops for the production of edible oil, whereas linseed is being cultivated for industrial applications. Rapeseed oil, sunflowerseed oil, and linseed oil contain approximately 60% oleic acid, > 60% linoleic acid, and < 60% alpha-linolenic acid, respectively. On account of these pronounced differences in their fatty acid patterns, each of these three oils yields a distinctly different product when it is treated with an agent reacting with double bonds. The same applies to the mixtures of fatty acids that are derived from these oils by hydrolysis as well as the mixtures of methyl esters that are obtained by methanolysis, and the mixtures of alcohols produced by hydrogenolysis, oleic, linoleic, and alpha-linolenic acids constitute valuable starting material for the chemical or enzymatic semi-synthesis of biologically active compounds of high value; the isolation of these fatty acids in a pure state is, however, rather laborious and time-consuming. Obviously, the great potential of rapeseed, sunflower kernels, and linseed, also of rapeseed, sunflowerseed, and linseed oils as well as of oleic. linoleic and alpha-linolenic acids is far from being fully exploited. It may be anticipated that numerous novel products can be developed if a 'deconstructivistic technology' is employed in order to preserve complex structures as far as possible from the morphological to the molecular level. Renewable resources should be degraded with restraint. Semi-synthetic as well as biotechnological techniques should be employed to produce compounds such as biologically active lipids.